Concrete pipe molding assembly



Dec. 29, 1970 a. 0. SMITH CONCRETE PIPE MOLDING ASSEMBLY Filed March 1,1968 F/GJ INVENTOR BURTON 0. SMITH ATTORNEY United States Patent3,550,225 CONCRETE PIPE MOLDING ASSEMBLY Burton D. Smith, 1014 HiltonSt., Monroe, La. 71201 Filed Mar. 1, 1968, Ser. No. 709,616

Int. Cl. B28b 21/16 US. Cl. 25-30 10 Claims ABSTRACT OF THE DISCLOSURE Aconcrete pipe molding assembly having vertically disposed, coaxial,outer and inner forms, spaced to provide an annular pipe-forming areathere-between. The inner form or core is vertically slidable in theouter form and has associated therewithin a detached, underlyingvibrator which, in the operation of the assembly,- is urged into contactwith an abutment on the inner form to consolidate the concrete mix fedto the space between the forms. Means are provided for slidablyretracting the inner form after the mix has been consolidated to therequired extent, and an adjustable stop is adapted to halt the upwardmovement of the vibrator and limit its contact with the inner form justbefore the inner form rises outof the bell ring of the outer form. Afterretraction of the inner form, the outer form is removed, leaving theformed pipe on the curing floor.

OBJECTS For many years, concrete pipe sections, especially those havinginside diameters of 6" through 24" and lengths from 4' to 8', have beenproduced on packer head machines, and while such machines will press themoist concrete tightly against the outside form or mold, the processlacks the facility of encouraging the particles in the mix to seek theirmost favorable position. Therefore, various methods to accomplish thispurpose of particle placement by vibration have been developed.

Most of these vibrating machines are of such a nature as to seriouslydamage the forms because they are physically connected to one form orthe other. Furthermore, they are relatively slow, usually making use ofcumbersome means in the application of pressure to the spigot or upperend of the pipe section. This has been necessary in order to make thepipe section conform to the finer detail normally found at that end ofthe pipe.

The primary object of the present invention is to provide a concretepipe manufacturing assembly employing a vibrator which avoids damage tothe forms and utilizes an inner form or core which is relativelyexpendible.

Another object of the invention is to provide a pipe forming assemblyincluding a vibrator which, while completely detached from the core, isselectively pressed against it during operation.

Still another object of the invention is to provide means formaintaining abutment of the vibrator and core in such a manner as toavoid rigid connections between the two which would result in tearing ofthe metal and shorter core life.

A further object of the invention is to provide an assembly such asdescribed, wherein the vibration can be stopped instantly as far as itseffect on the moist concrete is concerned. By having the vibrator followthe core as it is withdrawn from the newly formed pipe until it contactsa stop which is placed in optimum position to insure discontinuance ofvibration before the core clears the bell-forming ring, damage to thepipe is prevented.

With the above and other objects in view which will appear as thedescription proceeds, the invention consists in the novel featuresherein set forth, illustrated in the 3,550,225 Patented Dec. 29, 1970accompanying drawings, and more particularly pointed out in the appendedclaims.

THE DRAWINGS Referring to the drawings in which numerals of likecharacter designate similar parts throughout the several views:

FIG. 1 is a more or less diagrammatic view of the as sembly in sideelevation;

FIG. 2 is an enlarged, transverse, sectional view taken on line 22 ofFIG. 1, illustrating the bottom master pallet; and

FIG. 3 is an enlarged, vertical, sectional view through the outer formand inner core assembly.

In the drawings, 5 generally represents the vertical frame of themachine and preferably extends upwardly from a well 6 in the floor, asis conventional. Cross-bars 7 extend across the frame just below floorlevel and are spaced to support the bottom master pallet 8 which, aswill be seen from FIG. 3, comprises a plate having a central opening 9and provided on its upper face with a series of lugs 10 for centeringthe bottom or bell section 11 of the outer form 12. As upper masterpallet 13, having a central opening 14, centers the upper end of theouter form 12, and its lower surface is provided with tfiownwardlyprojecting lugs 15 for centering the outer orm.

It may be noted that the outer form may be of the type made up of twohalves with throw latches to fasten the halves together, or it may be ofthe type designed to strip vertically from the newly made pipe andconstructed in one piece. For purposes of understanding this invention,the type of the outer form is immaterial, and therefore it is shown moreor less diagrammatically in the drawings.

The inner form or core 16 comprises a cylinder of suitable metal of adiameter sufiiciently less than the outer form 12 to provide an annularspace for receiving the concrete mix to be used in forming the pipe. Theupper end 17 of the core is conical in shape, protruding through thecentral opening 14 of the top master pallet 13, where it is connected toa shaft 18 by a rubber coupling 19. The shaft 18 is under the control ofand hydraulic ram 20 at the upper end of the frame 5, thus the positionof the core 16 within the outer form 12 is controlled by by the shaft 18and ram 20.

It the form of the invention shown, the bottom of the core 16 is openand provided with an inset vibrator block 21 which, as will laterappear, provides an abutment for the vibrator 22, as best seen in FIG.3.

The details of the vibrator per se are not important to the presentinvention, as there are a great many different types of commercialvibrators on the market which may be used. Some of these are powered byair and others by electricity, and in either case, most of them producethe vibration by the high speed rotation of an eccentrically loadedshaft.

The vibrator 22 is provided with a downwardly extending shaft 23, thelower end of which projects through openings in two cross-bars 24 and25, as seen in FIG. 1. Preferably, the shaft 23 passes through rubberbushings 26 in the cross-bars 24 and 25 to minimize the transfer of thevibration to the frame, and a coil spring 23a is interposed between thebottom of the vibrator 22 and the upper cross-bar 24. Beneath thecross-bar 25, the shaft 23 is provided with a stop collar 27 which isadjustable on the shaft to control the upward movement of the vibratorand to regulate the point at which the vibrator ceases to contact thevibrator block 21 on the core 16.

The lower end of the outer form 12 is provided with a bell forming ring28, having a central opening 30 which encircles the lower end of thecore 16 and rests upon a support ring 29 on the inner face of the flaredend 11 of the outer form. The opening in the bell ring also acts tocenter the lower end of the core in the outer form.

The purpose of the coil spring 23a is to maintain contact between theupper end of the vibrator 22 and the vibrator block 21 within the limitsof the selected placement of stop collar 27 on shaft 23. It is felt thatthis method of mounting the vibrator would be most satisfactory andwould be used except in machines producing pipe sections longer than 4'or larger than 12" in inside diameter. For the larger sizes and longerlengths, it would probably be necessary to use a ram for controllingcontact of the vibrator with the core so that the vibrator could bewithdrawn below the elevation of the base ring to facilitate the removalof the finished pipe from the machine. Furthermore, larger or longerpipe sections would probably require that the vibrator be positionedhigher, i.e. nearer the center of gravity of the pipe section.

Adjacent the upper end of the forms, a hopper 31 is provided for feedingsuitable concrete mix to the forms by means of an endless conveyor 32.This is all conventional machinery and need not be described in detail.

In operating this assembly, it is necessary that the top master pallet13 be raised and lowered to release and engage the top of the outsideform. This is accomplished by the use of rams 33, operatively connectedby members 34 to the top master pallet 13, as diagrammatically shown inFIG. 1.

In operation, after the outer form and core are assembled as described,the concrete mix, in an earth moist condition, is poured into the spacebetween the upper end of the core and the outer form, the conical shapeof the core at this point automatically deflecting the mix into thespace between the two forms. The vibrator is then started, and as theconcrete is fed into the form, the vibration of the core 16 by thevibrator 22 causes the proper distribution of the mix in forming thepipe. After a suitable interval of vibration, the core form is retractedby the ram 20 and shaft 18, and just before the core form rises out ofthe bottom pallet and bell ring, the upward travel of the vibrator 22ceases because of contact of the stop collar 27 and the cross-bar 25, sothat its contact with the core 16 is broken. The retraction of the coreform continues until its bottom is above the top of the upper masterpallet 13. The upper pallet is raised by the rams 33, and the outer formcontaining the bottom pallet and the newly formed pipe is removed fromthe machine. The outer form is removed from the newly formed pipe whichis left standing on the bottom pallet on the curing floor. It isestimated that this complete cycle takes less than one minute.

Although forming no part of the present invention, a bell ring turningstand may be employed to rotate the bottom pallet as the pipe is beingformed so as to produce a smooth inner surface on the female end of thepipe. Also, means may be provided for rotating the core for this samepurpose on the pipe inside.

It is to be noted that one of the primary advantages of the presentarrangement resides in the fact that the vibration of the core may bestopped without stopping the upward movement of the core. This willgreatly facilitate the removal of the core from the newly formed pipewithout danger of damaging the pipe. In conventional machines embodyingvibrators which are fixed either to the core or the outer form, thevibrators must be shut off, and the core cannot be withdrawn until theyrun down because the vibration will shake the pipe down. Furthermore, bystarting the movement of the core with the vibrators stopped, after theconcrete has been properly consolidated by vibration, it would almostcertainly result in tearing the finished product.

Another advantage of the invention is that it provides compaction of themix in the spigot end of the pipe. This is accomplished by the conicalupper portion of the core. As the core is withdrawn, its conical upperportion presses the concrete mix against the outer form, the top masterpallet and the top forming ring.

From the foregoing, it is believed that the invention may be readilyunderstood by those skilled in the art without further description, itbeing borne in mind that numerous changes may be made in the detailsdisclosed without departing from the spirit of the invention as setforth in the following claims.

I claim:

1. A concrete pipe molding assembly comprising an open-ended outer form,means supporting said form in vertical position, a coaxial inner core,retractible through the upper open end of said form, means connected tothe upper end of said core for supporting and independently retractingthe latter through the adjacent open end of said form, said core havinga transverse abutment, a vertially moveable vibrator extending throughthe lower open end of said outer form and underlying said abutment, saidvibrator being completely detached from said outer form and core, meansnormally urgin said vibrator into physical contact with said abutment tovibrate said core when the latter is in its lowermost position withrespect to said outer form and for maintaining continued vibratingcontact with said abutment for a predetermined time during theretraction of said core from said outer form, and stop means fordefining the limit of the upward movement of said vibrator and itscontact with said abutment.

2. An assembly as claimed in claim 1, wherein said means for supportingand retracting the core comprise a connecting shaft and an hydraulicram.

3. An assembly as claimed in claim 2, wherein said shaft is connected tosaid core by a rubber coupling.

4. An assembly as claimed in claim 1, wherein said means for urging saidvibrator into contact with said abutment comprises a coil springinterposed between said vibrator and an underlying fixed cross-bar.

5. An assembly as claimed in claim 4, wherein said vibrator is providedwith a depending rod and said stop means comprise a stop collarvertically adjustable on said rod, and fixed means engageable by saidcollar to limit the upward movement of said rod.

6. An assembly as claimed in claim 5, wherein said depending rod passesthrough a resilient bushing in said fixed cross-bar.

7. An assembly as claimed in claim 1, including top and bottom masterpallets for retaining said outer form in place and centering the same.

8. An assembly as claimed in claim 1, wherein the lower end of saidouter form is provided with a bell-forming ring.

9. An assembly as claimed in claim 8, wherein said bellforming ring hasa central opening to receive and center said core.

10. An assembly as claimed in claim 1, wherein the upper end of saidcore is conical in shape to facilitate compaction of the mix at thespigot end of the pipe.

References Cited UNITED STATES PATENTS 2,679,384 5/1954 Livingston 2541x 3,078,539 2/1963 Duplessis 25-30 3,083,433 4/1963 Tiller 25-393,119,165 1/1964 Gourlie 25 30 3,273,216 9/1966 Gourlie 25- 30 J.SPENCER OVERHOLSER, Primary Examiner BEN D. TOBOR, Assistant ExaminerUS. Cl. X.R. 2541

